216 MINERAL WATERS, WELL WATERS, ETC. 



IV. The solution filtered from the precipitate is 

 mixed with ammonia, and the magnesia precipitated 

 by phosphate of soda. (See No. 6.) 



V. Another portion of the incrustation is dissolved 

 in hot dilute hydrochloric acid, and the sulphuric acid 

 precipitated by chloride of barium (No. 3). 



VI. A smaller quantity is dissolved in dilute nitric 

 acid, and the chlorine precipitated by nitrate of silver 

 (No. 1). 



VII. The sodium and soda are calculated from the 

 loss. 



VIII. In order to detect a small quantity of sulphate 

 of potassa, a large quantity of the incrustation is 

 finely powdered, boiled with an excess of hydrate of 

 baryta, the solution filtered off, the lime and baryta 

 precipitated by a mixture of ammonia and carbonate 

 of ammonia, the filtrate acidified with hydrochloric 

 acid and evaporated to dryness ; the residue is ignited, 

 dissolved in water, and the solution treated with bi- 

 chloride of platinum. 



In this process also, the soda which previously 

 existed as sulphate, may be obtained in the form of 

 carbonate. 



116. MINERAL WATERS, WELL-WATERS, SALINE 

 SPRINGS. 



It is supposed that the analyst has an unlimited 

 quantity of water at his disposal, so that separate 

 portions may be employed for the determination of 

 most of the individual constituents. For the estima- 

 tion of those substances which are present in large 

 quantity, small portions of water must be employed, 

 larger quantities being taken for such constituents as 

 exist in small proportion. 



I. The specific gravity is first determined, in order 

 to ascertain, by calculation, the weight of 10, 50, or 



